A biosensor may be a device for the detection of an analyte that combines a biological component with a physicochemical or physical detector component.
Magnetic biosensors may use the Giant Magnetoresistance Effect (GMR) for detecting biological molecules being magnetic/magnetisable or being labeled with magnetic/magnetisable beads.
In the following, biosensors will be explained which may use the Giant Magnetoresistance Effect.
WO 2005/010542 discloses the detection or determination of the presence of magnetic particles using an integrated or on-chip magnetic sensor element. The device may be used for the magnetic detection of the amount of binding of biological molecules on a micro-array or biochip. Particularly, WO 2005/010542 discloses a magnetic sensor device for determining the presence of at least one magnetic particle and comprises a magnetic sensor element on a substrate, a magnetic field generator for generating an AC magnetic field, a sensor circuit comprising the magnetic sensor element for sensing a magnetic property of the at least one magnetic particle which magnetic property is related to the AC magnetic field, wherein the magnetic field generator is integrated on the substrate and is arranged to operate at a frequency of 100 Hz or above.
JP 8178823 discloses a system for measuring viscosity of viscous material. Shortening the measuring time while sustaining accuracy shall be obtained by employing fine particles of a soft magnetic material as a measuring means and moving the fine particles forcibly at a high speed by applying a magnetic field externally thereto. Fine particles of a soft magnetic material may be produced by quenching the molten soft magnetic material. The fine particles may have a spherical shape and the particle size may be arranged by means of a sieve or a gas flow classifier in order to make the resistance of a viscous material uniform during movement of the fine magnetic particles. When the viscosity is measured, the magnetic fine particles are arranged in a measuring vessel filled with a viscous sample material to be measured and a magnetic field is applied to the vessel from the outside thus moving the magnetic fine particles forcibly at a high speed. The moving speed or moving time is then detected in order to measure the viscosity and the moving speed or moving time itself is an indicator for/measure of viscosity.
However, sufficient accuracy of measurement results may still be problematic under certain circumstances.